@article{oai:repo.qst.go.jp:00043025,
 author = {Yanagisawa, Kei and Takeda, Hiroshi and Miyamoto, Kiriko and Fuma, Shoichi and Ishii, Nobuyoshi and 柳澤 啓 and 武田 洋 and 宮本 霧子 and 府馬 正一 and 石井 伸昌},
 journal = {Journal of Radioanalytical and Nuclear Chemistry},
 month = {Apr},
 note = {Tracer experiments on the transfer of carbon from culture solution to Daphnia magna through phytoplankton have been carried out using 13C and infrared absorption method. The purpose of this experiment is to investigate the experimental systems for the use of 13C in aquatic system. Daphnia magna was cultured in a 100ml of solution containing phytoplankton and 20mg of NaH13CO3  for 24 hours in the light and dark condition( 2000 lux, 14houre light and 10 hours dark at 25 degree-C). The concentration of 13C in Daphnia magna under light condition was about 2.0% (atom% excess), while in the dark condition 13C tracer was not detected. The concentration of 13C in phytoplankton under light condition was around 20%. It was suggested that 13C added as carbonate in the culture solution was photosynthetically assimilated by phytoplankton and then transferred to Daphnia magna. Using this system effect of UV-B exposure on the 13C uptake of Daphnia magna has been examined. The UV-B intensity was 95 mu W/cm2 and exposure time was 15, 30, and 60 minutes. The concentration of 13C in Daphnia magna was decreased according to the exposure time. The Daphnia magna exposed to UV-B for 15 minutes intakes phytoplankton as much as control, while 30minuts and 60minuts exposure were lower than control. The lower concentrations of 13C observed in Daphnia magna was due to less intake of phytoplankton caused by the UV-B exposure.},
 pages = {277--280},
 title = {DETERMINATION OF 13C CONCENTRATION IN BIOLOGICAL MATERIALS USING INFRARED ABSORPTION METHOD},
 volume = {252},
 year = {2002}
}